The second-to-last photograph [1] taken by Namir Noor-Eldeen shows an American Humvee and the radio calls make it clear that there is a ground force in the vicinity which was reporting a contact with the individuals on the ground, was able to see the individuals at various points in the action and was close enough that it took only 8 minutes for them to mount up and arrive on the scene. This group (apparently "Bushmaster element") appears to be the one which radios "Yeah, we had a guy shooting. And now he's behind the building" at 04:22.
Your assertion that there were no Iraqi or coalition ground forces in the area is not supported by the video.
They need to drive 8 minutes to get to the scene, when they are "near"? Even when halving the time for mounting and going by 20kmh they were 1km around 1.5km away. Near? What does "in the area mean"? Bagdad?
If you read the official documents on the investigation of the incident, including the sworn affidavits, the ground forces were 100-200 meters away throughout the entire thing.
Merely halving the time for mounting and assuming a 20km/h travel speed without any stops (bearing in mind this is a combat zone) seems a bit arbitrary. In any case, the radio calls seem to affirm that the ground element was in visual range of the people before the gunships even opened fire and Namir's photo, if it was indeed taken at the scene as we assume, shows the ground force as being pretty close, perhaps no more than 100-300 m away.
If they were 100m away, why did it take them several minutes to arrive while the helos circled? Even when crouching (from my exp in the the army), looking for ambushes during house fighting you're faster going down a street than this.
Maybe they had soldiers spread out and it took a while to call them back and mount up? Maybe one of the vehicles had mechanical problems? Maybe they even decided to hold for a few minutes to wait and see if any more surprises would show up? We can't know.
Regardless, this discussion is now irrelevant, as it has been confirmed elsewhere that the photo I posted above was taken at this scene, presumably while Namir was peeking around the corner. That photo shows US troops no further than 200 m away, if I recall that lens's capabilities correctly.
Your assertion that there were no Iraqi or coalition ground forces in the area is not supported by the video.
[1] http://duckbar.mirror.waffleimages.com/files/c7/c76f1e685afe...